A new combination and two varieties of polystigmate Gomphonema (gomphonemaceae bacillariophyta) from Heilongjiang Province, China

The authors discribed a new polystigmate combination,Gomphonema turris Ehr. var.okamurae (Skv.) Fan et Bao. comb. nov., and two new varieties,Gomphonema turris Ehr. var.latum Fan et Wang. var. nov. andGomphonema acuminatum var.obtusum Fan et Bao, var. nov., that were distinguished by frustule morphology under LM. The samples were collected from freshwater of Heilongjiang Province, China. Project No. 39899400 supported by the NSFC.     

The initiation and development of metamorphic foliation in the Otago Schist, Part 1: competitive oriented growth of white mica

The 3D shape, size and orientation data for white mica grains sampled along two transects of increasing metamorphic grade in the Otago Schist, New Zealand, reveal that metamorphic foliation, as defined by mica shape‐preferred orientation (SPO), developed rapidly at sub‐greenschist facies conditions early in the deformation history. The onset of penetrative strain metamorphism is marked by the rapid elimination of poorly oriented large clastic mica in favour of numerous new smaller grains of contrasting composition, higher aspect ratios and a strong preferred orientation. The metamorphic mica is blade shaped with long axes defining the linear aspect of the foliation and intermediate axes a partial girdle about the lineation. Once initiated, foliation progressively intensified by an increase in the aspect ratio, size and alignment of grains, although highest grade samples within the chlorite zone record a decrease in aspect ratio and reduction in SPO strength despite continued increase in grain size. These trends are interpreted in terms of progressive competitive anisotropic growth of blade‐shaped grains so that the fastest growth directions and blade lengths tend to parallel the extension direction during deformation. The competitive nature of mica growth is indicated by the progressive increase in size and resultant decrease in number of metamorphic mica with increasing grade, from c. 1000 relatively small mica grains per square millimetre of thin section at lower grades, to c. 100 relatively large grains per square millimetre in higher grade samples. Reversal of SPO intensity and grain aspect ratio trends in higher grade samples may reflect a reduction in the strain rate or reduction in the deviatoric component of the stress field.     

The Location of Creativity and U.S. Companies in Germany

This article analyzes how far U.S. companies locate subsidiaries in need of highly skilled staff in state locations in Germany that have a high ranking of creativity. Such locations should provide an especially attractive location for certain “creative” staff, which should be of special interest to U.S. companies in need of highly skilled staff. Analyzing U.S. companies that were established since the year 2000 and with more than fifty staff, we find support for our propositions that nonmanufacturing and organizationally higher rank subsidiaries with a need for urban infrastructure and connectedness are located in creative states in Germany.     

多尺度知识溢出研究——以进出口互动效应为例

知识溢出是地理学探究的重点话题。知识可以在不同的地理尺度上溢出,其效应具有差异化的表现。本文选择进出口互动效应作为知识溢出成果的表征,并基于2002—2015年中国海关进出口贸易数据,实证测度了企业从进口侧所导入的知识在企业内部、区域内部以及区域之间三个地理尺度上的溢出对企业出口所造成的影响。研究发现,在全国范围内,企业自身和企业所在的区域进口新品种的产品,能显著促进企业出口新品种的产品,且前者的促进效应更强。同时,企业邻近区域进口新产品,对本地企业出口新产品存在负向影响。然而,该影响在发达地区中表现为负,在欠发达地区表现为正。文章结果反映了不同地理尺度上的知识溢出具有差异化的表现,溢出效应存在距离衰减特征。本文丰富了地理学对于知识溢出话题的认知,具有一定的理论和现实指导意义。     

Application of fuzzy clustering and fuzzy classification to evaluate the provenance of glacial till

To evaluate the provenance of glacial till, the trace element content of magnetite was used. Magnetite was present in all known rock types and all till samples in the area investigated. By using fuzzy-set theory it was possible to group samples of magnetite taken from bedrock into relatively homogeneous and geologically meaningful groups and also, by fuzzy classification, to relate the till samples to the rocks in such a way that the relative contribution of each rock type to the till is estimated. Each rock and till sample is assigned a membership value between 0 and 1 for each rock type. The membership values, for a certain rock type in the till, are then interpolated by kriging onto maps. Magnetites from skarns associated with sulfide ores especially are rather distinct, and so a map of such membership values for till unveils all known ore deposits some 1–5 km downstreamin the general direction of the ice flow. Other anomalies show up which cannot be related to hitherto known ores or mineralizations.     

华南两个不同成因系列花岗岩的云母标型特征

研究表明,云母特征可作为两个不同成因系列花岗岩的判别标志和成岩成矿演化的示踪。系列Ⅰ中特征矿物组合为铁质黑云母+白云母+钛铁矿+富铝硅酸盐;系列Ⅱ为镁质黑云母+角闪石+磁铁矿+贫铝硅酸盐。M(M=Mg/Mg+Fe~(2+)+Mn)是一个可靠的判据。系列Ⅰ:M<0.45,系列Ⅱ:M>0.45。两个系列云母的化学组成的明显差别主要受控于物源成分的差异。两个系列云母的差热曲线和红外光谱特征也明显不同。用Li-Mg-Fe~(2+)+Mn三角图可以反映成岩成矿演化趋势。     

云母含量对风化花岗岩路基土工程性质影响的试验研究

通过从花岗岩残积土中分离出云母 ,按云母含量的不同配制试件进行承载比试验、回弹模量试验 ,研究云母含量对花岗岩路基土工程性质影响的复杂规律 ,探讨花岗岩路基土工程性质变化的机理。     

The structure and the phyllosilicates (chemistry, crystallinity and texture) of Talas Ala-Tau (Tien Shan, Kyrgyz Republic): comparison with more recent subduction complexes

Geological mapping and structural analysis of the Talas Ala Tau (Tien Shan, Kyrgyz Republic) have revealed a complex structure composed of folds with axial-plane cleavage and thrust faults verging towards the NE. The main structures of the range correspond to minor Tertiary and Carboniferous–Permian deformation superimposed on the main deformation event that took place during the Baikalian orogeny. The pervasive axial-plane cleavage diminishes in penetrativity from the hinterland to the foreland in both the Uzunakhmat and Karagoin sheets. The main thrusts developed phyllonitic shear-related rocks on the hangingwall immediately above the thrust planes. A crystal-chemical study of the phyllosilicates growth during the Baikalian deformation event along a cross-section revealed changes in the crystallinity, composition and lattice parameters of them. The phyllosilicates present in the Talas Ala Tau rocks were crystallized in very low-grade metamorphic conditions, that is below 300 °C, as indicated by their Kübler Index (KI), which decreases from SW towards the NE. Detailed TEM study of the phyllosilicates reveals a clear textural difference at the lattice level between samples with higher or lower KI parameters. There is also a clear difference in crystal-chemical parameters (KI and b) and composition between the phyllosilicates growth in relation to the axial-plane cleavage and the ones belonging to the thrust-related phyllonites. The first ones are more affected by the ferrimuscovitic vector than the phyllosilicates of phyllonites, closer to the theoretical phengitic component. Huge ranges of values of phengitic content of micas at sample level are interpreted as the result of a decompression path from at least 8 kbar. We propose a subduction geodynamic environment for the regional deformation and the origin of the phyllosilicates, as they are similar to those obtained in more recent accretionary complexes.     

碎云母的工业用途及开发

云母类矿物是一种非常重要的非金属矿产资源,具有多种优良性能,因而广泛应用于现代工业部门。就世界范围讲,片云母的产量已逐年下降,碎云母的用量大幅度提高,故今后的云母资源将转向开发碎云母。本文论述了碎云母的矿物学特征、工业用途,并简要探讨了其开发途径。     

H2O Content Measurement in Phengite by Secondary Ion Mass Spectrometry: A New Set of Reference Materials

Five new natural white mica reference materials (RMs) were developed for in situ H₂O content analyses by secondary ion mass spectrometry at the SwissSIMS laboratory of Lausanne University, Switzerland. The white mica reference materials cover a large part of the natural muscovite–phengite compositional range and are therefore suitable as reference materials for the analysis of natural rocks as well as individual minerals. The independent H₂O content of the reference materials UNIL_WM1 to UNIL_WM5 was obtained by thermal conversion elemental analyser and corresponds to 4.35 ± 0.02, 4.33 ± 0.03, 4.30 ± 0.07, 4.50 ± 0.02 and 4.42 ± 0.11 (% m/m, ± 1s), respectively. SIMS determinations of H₂O content revealed a matrix effect correlated to the FeO content of white mica. The compositional range in FeO of the reference materials that were calibrated for H₂O determination is from 1.13% to 3.67% m/m. No crystallographic orientation dependency was observed at the level of homogeneity of these reference materials. An analytical precision of 0.02% to 0.08% m/m (1SE) is expected for the final uncertainty on measurements of unknown white micas in natural samples.